My 360 gave me the 3 Red Lights about a week ago and tonight I attempted to do the X-Clamp replacement but I had trouble... I couldn't actually get the X-Clamps off and I thought the console was destined to be a paper weight however, I applied pressure to the corners of the clamps just by pushing on them with me fingers (hoping and thinking that for some reason it would help!?) then plugged the system back in leaving off the fans and the DVD drive, as suspected I got the three red lights but I thought 'hey lets leave it running till it overheats' so I did, when it had over heated I got the two red lights so I turned off the console and replaced the fans and DVD, powered back on again and now the 360 is working perfectly well!
I really don't know what caused it to come back to life, I may be a dumbass but hey, it worked!